Production of a front section of a writing implement, comprising a one-piece preform

ABSTRACT

The invention relates to a front section ( 1 ) of a housing of a writing implement. Said front section comprises a casing body ( 4 ) consisting of a shape-retaining substance and a jacket ( 8 ) consisting of a second substance, which forms a flat surface surrounding the casing body along a substantial part of said body&#39;s axial length. An opening ( 7 ) positioned at the front of the tip of the casing body ( 4 ) forms the starting point of an adjoining axial segment ( 7, 10 , k 1 ) of an injection canal ( 38, 39, 10, 24, 25 ) for the second substance. The casing body ( 4 ) has at least one radially oriented aperture ( 14 )

[0001] The invention relates among others to the production of a frontportion of a housing or for a housing of a writing instrument having arefilling device (refill), said front portion comprising a sleeve bodymade of a shape-retaining material (preform) and a jacket covering asurface of said sleeve body along a substantial part of a lengththereof, said jacket being made of a material having elastic grippingproperties. When said writing instrument is used, said jacket serves asa gripping zone which is adapted to give a good hold to a user'sfingers. For this purpose, the outer surface of said jacket can alsohave a conical extension. Said jacket can be adapted to have an elasticductility appropriate to the purpose.

[0002] In writing instruments comprising a front part that, for a betterhandling, is mostly adapted to have a conical extension, sprue portionsof elastic materials cause problems, since the material tears offuncontrolledly when being separated or detached from a mold. Therefore,efforts are made to hide said sprue portions. When hiding said sprueportions and when covering a front part of a writing instrument at anoutside thereof from an inside and through walls thereof with a materialthat has elastic gripping properties, a conducting channel for athermoplastic melt cannot be adapted to extend through a refill opening(refilling device opening or guiding and penetration opening), sincesaid opening is adapted to usual refilling devices, thus having adiameter which is too small for sufficiently economically providing aguiding channel with cores. Therefore, it is necessary to adapt a frontportion of a front part of a writing instrument to have a largerdiameter for initially applying a circumferential jacket made of amaterial that has elastic gripping properties around said front portion,and for subsequently, in a further working step, applying a tip portionby ultrasonic welding or friction welding. Only then, said subsequentlyprovided tip portion can be adapted to have a diameter at a front endthereof which is small enough to laterally support the refilling device.

[0003] Therefore, a one-piece sleeve body cannot be used, on thecontrary, due to production processes, a two-piece sleeve body isinevitably required, said sleeve body comprising a first portion and atip portion applied subsequently. An object of the invention is toreduce the cost for producing such front parts of writing instruments,and further to keep sprue portions of soft parts hidden, even if aone-piece sleeve body is used as a blank for receiving a portion whichis applied circumferentially (said portion having elastic grippingproperties).

[0004] In order to simplify production and to reduce production cost,the invention provides a penetration and guiding portion at the tip of asleeve body (refill opening), said portion being adapted as a portion ofan injection channel for a material of an outer jacket, said materialhaving elastic gripping properties (claim 13, 30), at least partlycircumferentially in a radially outward direction, without a metallicsupport of a ram-shaped core which is (relatively) moved into saidsleeve body in front of a rear end thereof. Said core either starts onlybehind said channel segment of said blank (24), at or from a diameterallowing a practical application of a material conduct in said core, orhas a channel conduct that is open towards an outside (claim 25).

[0005] Said sleeve body (claim 1) has at least one aperture in a jacketportion thereof through which a material forming a gripping zone isconducted from an inside towards an outside, from said injection channelsegment to an outer circumferential portion of said sleeve body. One ofsaid penetration and guiding opening at said tip of said sleeve body andan adjoining portion of said inside of said sleeve body can be adaptedas a portion enlarging towards said inside of said sleeve body or as aportion having an undercut (claim 2,9,14).

[0006] Due to said properties and to the ability of injecting a materialsupplied as a second material, particularly a thermoplastic elastomer,by using a two-component injection molding technology through a refillopening provided in said sleeve body to a circumferentially limitedextent, said sleeve body itself can be provided in one piece —without aweld or a connecting seam—, thereby substantially simplifying andaccelerating the production of a front part of a writing instrument, andthus reducing production cost (claim 1).

[0007] For obtaining a better attachment by complementary shapes betweensaid jacket and said sleeve body, said sleeve body can be provided withat least two apertures distributed over a circumference thereof, saidapertures being filled in when forming (injection molding) saidsurface-covering jacket. For improving said connection, at least one ofsaid apertures can be provided with a contour enlarging from and outsidetowards an inside thereof (claim 4, 15, 16); since there is no materialbond between the two materials of said two-component injection moldingtechnology (the materials do not stuck together), a better support ofsaid circumferential jacket at said—inside located—shape-retainingsleeve body is obtained by said mechanical arrangement, said supportalso having a surface effect.

[0008] A production in two-component injection molding technology (claim11,12) comprises a first component for producing a shape-retainingsleeve body of a relatively brittle plastic material, such as ABS; asecond component serves for producing a jacket and uses a thermoplasticelastomer (TPE). Initially, a shape-retaining sleeve-body is produced,said sleeve body comprising a penetration and guiding opening (for arefilling device inserted later) and at least one, preferably twoapertures in a circumferential wall thereof. An elastomer forming anouter jacket is applied along a considerable length—a multiple of thediameter of said refill opening—of said circumferential wall, far into atip portion, said elastomer being injected through a penetration andguiding opening of said sleeve body into an inner space thereof,particularly being contactingly supported and conducted, for beingguided from said inner space through said aperture(s) towards an outsideonto a circumferential wall of said sleeve body, and for being shaped onsaid circumferential wall to obtain a continuous circumferential jacket.

[0009] It is not disturbing that, after penetrating into the penetrationand guiding opening inside said sleeve-body, the stream of said secondmaterial, when being injected, is initially enlarged in cross-section,said second material being only subsequently conducted to an outsidethrough an aperture of said preform (claim 17,19). During production,said penetration and guiding opening (refill opening), which has one ofa cross-section enlarging towards an inside of said sleeve body and anundercut, is blocked by an inserted core as of an axial position (claim17), said position being located behind, particularly markedly behind afront end of said refill opening. Thus, said refill opening (tipopening) forms part of an “injection channel” conducting a melt of saidsecond material, and can therefore be small in diameter (claim 9,31)—corresponding to a refilling device inserted later—without opposinga too high flow resistance to said injection process in a post pressurephase. Inserting a core extending to a front end for guiding said meltis dispensable (claim 24).

[0010] A particular embodiment of a top portion of said core can resultin said core still extending further into said tip portion, up to saidrefill opening, nevertheless maintaining the inventive idea. However, insaid portion, no inside guiding channel of said core is required, saidcore having a metallic outside cover, on the contrary, at least oneportion of a circumference (in case of laterally open channels) or theentire circumference (in case of a core having a conical top portion) ofsaid inside surface of said sleeve body is used for closing the guidingchannels left open by said top portion of the core. Said guiding channelcan have an annular shape (claim 28). A plurality of combinations arepossible, starting from a shorter core not extending completely up tosaid refill opening, but leaving an axial length free (claim 24, firstalternative, claim 26, claim 6, claim 30). At least one wall piece of aguiding channel is provided forming an axially and circumferentiallyextending wall portion of a guiding channel, said guiding channelreceiving the melt of said second material and conducting it to arespective aperture (claim 7, 8). A length of said respective wall pieceis at least one half of a diameter of said refill opening, said lengthparticularly being larger than said diameter of said refill opening(claim 5, 9, 32).

[0011] Being located at an inside (claim 10), the sprue portions(separating portions) of said jacket having elastic gripping propertiesare allowed to tear off uncontrolledly upon separating sprue channels,thus not disturbing the handling nor the outer appearance.

[0012] Said sleeve body can be embodied in one piece, even if a frontopening thereof is adapted to a usual diameter of a refilling device,thus being too narrow for additionally receiving a core which,additionally, would have to comprise an inner channel for transporting asoftened plastic material. By simultaneously using a short, but markedportion of said tip as a guiding channel segment (also “sprue channelsegment”), it is ensured that no additional narrow portions occur in theentire flow channel, so that during the injection process, a post ordwell pressure phase can be effected without problems to compensate ashrinkage of said second material. Nevertheless, a second productionstep required by additionally attaching a conical tip portion isdispensable, which has a favorable effect on the production cost.

[0013] A further advantageous effect of the invention is that thegripping zone can extend further into said tip portion, since asubsequent attachment of a tip portion having a length of about 1.2 to1.5 cm is not required. In principle, it would even be possible toapproach said elastic gripping zone from outside substantiallycompletely towards said refill opening, so that no visible blank of amore solid plastic material protrudes out of said gripping zone at afront end thereof any more.

[0014] Even a mold separation of a material thus injected which uses arefill opening predetermined by a diameter of a refilling device as achannel segment, is absolutely reliable, even if a usual sleeve body isprovided with a refill opening having a shape enlarging towards aninside. If said material has elastic gripping properties, even in asolidified state, it can nevertheless be removed in an axially forwarddirection, the connection portions being located inside shearing ortearing off. Preferably, said connection portions can have a muchthinner shape than the remaining channel portion, said connectionportions nevertheless hardly having any influence on the dwell pressurephase since they have a very short length (claim 10, 20, 18).

[0015] An additional improvement of said separation is obtained bycorrespondingly embodying the distribution channel pieces which areprovided in a core such that they radially deflect said TPE meltsupplied through said channel segment of said sleeve body. If theycomprise cut edges or at least sharp upper edges, a cull or slug orsprue can easily be removed by a puller core, even if said refillopening comprises a conical portion in a cone being adapted to extend inan opposite direction with respect to a removal direction (claim 19).Conical openings in a core are advantageous (claim 29).

[0016] A sleeve body comprising a plurality of apertures distributedover a circumference thereof serves for attaching or fixing said jacketat a plurality of positions of said sleeve body, all apertures beingfilled in with said jacket material (claim 3). However, saidthermoplastic material needs to be conducted out of said injectionchannel of said sleeve body only through one ore two of said apertures,the remaining apertures being filled in from outside, from said jacketportion (claim 16).

[0017] Inserting said core into said sleeve body has to be effectedcarefully, insofar as said sleeve body can be provided with a conicalthread and can therefore easily be ejected from its support by axialforces when said shaping space has not yet been closed. In order toavoid this, said sleeve-shaped blank is initially moved into saidshaping space, preferably by a pivoting movement, and received in itssupport, said core being inserted partly but not completely into saidblank, preferably by about 80% to 90%. (claim 21). Thereupon, a moldingor shaping plate is closed, said plate supporting an injection cavity,allowing said sleeve-shaped blank to be supported at a front end by acircular or an annular support line. Said blank having been supported,said core is completely inserted (claim 22), without ejecting said—nowsupported—blank from its support.

[0018] In the following, the invention is specified and supplemented inmore detail on the basis of embodiments.

[0019]FIG. 1 is a lateral view showing a front portion 1 of asleeve-shaped housing for a writing instrument having a refillingdevice—which is not illustrated.

[0020]FIG. 2 is a cross-section along a cutting plane II-II of FIG. 1.

[0021]FIG. 3 is a longitudinal section through a portion 1 as shown inFIG. 1.

[0022]FIG. 4 is a lateral view of a core 20 insertable when injecting asecond material, for further conducting and distributing said injectedmaterial.

[0023]FIG. 5 is a longitudinal section through an injection molding toolused for applying a jacket by injection molding.

[0024]FIG. 5a is a detail of the injection molding tool according toFIG. 5 with an inserted blank 4 and an alternative core 20.

[0025]FIG. 5b is a detail of the injection molding tool according toFIGS. 5,5a having a further alternative core 20.

[0026]FIG. 6a shows an embodiment of a top portion of a core (core head)according to FIG. 5a, wherein two openings 25 a,25 b crossing oneanother and extending at an angle are provided in said head portion 22of said core, said openings additionally being slightly conical.

[0027]FIG. 6b is a detailed view of a core head 22 a of the core 20according to FIG. 5b, said core head having a conical portion 22 b forforming an annular guiding channel 27 which is roughly illustrated inFIG. 6b, however visibly results from an inserted state of said coreaccording to FIG. 5b.

[0028]FIG. 6c is yet a further embodiment of a top portion 22 c of acore, which—as in all FIG. 6—is visible from the illustrated top planview in an axial direction. When inserting the core of FIG. 6c into thetool of FIG. 5, two axial channels 27 a,27 b which are axially orientedbut circumferentially limited in relation to FIG. 6b, have the effectthat a respective portion 10 a,10 b of a conical portion 10 according toFIG. 3 serves as a radially outer limitation of a respective guidingchannel, thus as an outer wall thereof, even if said core protrudesfurther into a refill opening according to the comparison of FIGS. 6a, 6b and 6 c.

[0029]FIG. 7 illustrates a cull or sprue 45 which has been removed in anaxially outward direction through an injection opening after finishing afront portion, said sprue inversely illustrating the shape of a refillopening 7,10 of a preform.

[0030] According to FIG. 1, a front portion 1 of a writing instrumenthousing, which is not illustrated, comprises an inner sleeve body 4 madeof a shape-retaining (solid) plastic material and a jacket 8 made of athermoplastic elastomer and covering a part of the length of said sleevebody 4. Said jacket extends between a tip portion 6 of said portion 1and a rear connecting portion 2 which can for example be provided with athread 5. Said tip has a penetrating and guiding opening 7 through whicha front end of an elongated refilling device protrudes—at least in awriting position—said refilling device being laterally guided andsupported; therefore, said opening is designated as “refill opening”.

[0031] Said surface-covering jacket 8 can be structured on an outersurface thereof for increasing the gripping property, for example beingprovided with a plurality of small recesses 9 or protruding naps.Structurally, said second material forming said jacket has elasticgripping properties for improving the main function of holding thewriting instrument at a gripping zone thereof.

[0032] In an axial longitudinal portion k3 which is surrounded orcovered by said jacket 8, said sleeve body 4 is provided with at leastone wall aperture 14. According to the embodiment shown in FIG. 2, fournarrow and elongated slots 14 are provided as apertures, said slotsbeing uniformly distributed in a circumferential direction. In afinished state, said apertures are completely filled in 14 a with thematerial of said jacket 8, thus forming a form-fitting connection (bycomplementary shapes)—not a bond by material—between the elastomerjacket material and said sleeve body 4.

[0033] In order to reduce the risk of a separation of said two parts 4,8in a radial direction, at least one peripheral surface or one of saidapertures 14 can have an undercut from the outside towards the inside,as shown at 15, at the support webs 14 a in FIG. 3. With reference toFIG. 2 it is visible that in FIG. 3, said sleeve body is cut on the leftside in a plane which is pivoted by 45° in relation to the cutting planeon the right side of FIG. 3.

[0034]FIG. 5 shows an injection molding tool 35 for applying a jacket byinjection molding, said tool being illustrated with an inserted core 20,however, without said sleeve body which forms part of said injectionmold for shaping said jacket. Said core 20 forms a shaping space 41together with an inner portion 36 of said mold, said shaping space beingfilled in with a prefabricated sleeve body 4 and a jacket material 8 tobe injected.

[0035] It can be seen from FIG. 3 that a tip portion 6 adjacent to saidrefill opening 7 of said sleeve body is conically enlarged 10 along alength k1. Said enlargement terminates at a plane 11. As from saidplane, the inside surface 12 of said sleeve body 4 is cylindrical.Behind said cylindrical portion 12, said surface is once again conicallyenlarged at 13, subsequently extending cylindrically or enlargingslightly up to a thread 5. Apertures 14 are located at a distance k2from an end 11 of said first enlargement 10. An outer wall 4 a of saidsleeve body 4 carries said jacket 8.

[0036] An outer mold comprising multiple parts according to FIG. 5serves for injecting said jacket material, said mold shaping the outerappearance or form of said jacket 8, whereas a mandrel or die 20 (in thefollowing designated as core), as shown in FIG. 4, can be inserted intothe inside of the prior-shaped sleeve body 4, said core nearlycompletely filling up the inside of said sleeve body 4. Said core 20 isadapted to the inner shape of said sleeve body 4 and comprises a conicalportion 21 adapted to a surface 13 and a top or head portion 22protruding into said cylindrical portion 12 and being adapted thereto,said top portion comprising a face end surface 23 and a body portion 20a which is very slightly conical.

[0037] Said face end surface 23 of said core 20 terminates in aninjection position at said plane 11 in front of said conical enlargement10 of said tip portion 6 of said sleeve body 4, thus substantially at adistance k1 from said refill opening 7.

[0038] Thus, in said injection position, the inside space of said sleevebody 4 is filled practically up to said plane 11 with said die 20.Together with said enlargement 10, said refill opening 7 forms aninjection channel along a length k1 for the injection process of thethermoelastic jacket material, into which injection channel said secondmaterial can be injected through channels 38,39 of said injection moldfrom a face end thereof. Below said injection channel segment 7,10,k1,said die 20 is provided with an opening 24, forming a receiving anddistributing channel segment for said injected material 30 together withlateral outlet openings 25, through which openings a material flow 31 isconducted to at least one of said apertures 14. Preferably, saiddistributing openings 25 are X- or V-shaped and start directly at saidface end 23.

[0039] It can be seen from FIG. 4 that in an inserted state, saiddistributing openings 25 end in an area of at least two apertures 14being located opposite of each other. Also, all apertures can beconnected with said receiving channel segment 24. However, it is alsosufficient to fill up some of said apertures 14 from said outer shapingspace 41, i.e. from the outside towards the inside.

[0040] In connection with said core 20, said sleeve body 4 comprisingsaid apertures 14 is adapted such that when separating or removing atleast one of the die and the shaped front portion 1 from said injectionmold, said material having elastic gripping properties is separatedfrom, e.g. torn off or sheared off, said jacket shaped at said sleevebody and from said thermoplastic material 14 a filling in said apertures14, said separation occurring at a peripheral surface between an innercircumference of said channel piece 24 of said core 20 and said sleevebody 4, so that a connection portion 45 c remains. Thus, a coherent cullor sprue 45 remains which is hardened in the channels 38,39 of saidinjection mold and in said injection channel 7,10 of said sleeve body 4as well as in said distributing channel(s) 24,25. For example, saidsprue or cull is removed from said channel segment 7,10,24,25 in anoutward direction using a puller core 40. Said cull or sprue remainder45 is illustrated in FIG. 7. Said removal does not cause any problemsdespite the cone-shape 45 k of said injection channel, since acorresponding elastomer material is used for said jacket, and thedistributing channels 44 a,44 b are separated at 45 a,45 b. Here are thethin portions of the injection molding channel.

[0041] Further components of an injection arrangement 35 are visible inFIG. 5a, said arrangement comprising an alternative core which will bedescribed later. The path of the material to be injected is indicated byarrows 30 and 31 in FIGS. 3,4. The procedure of positioning a blank 4 ona core 20 is indicated by an arrow 46 for illustrating the relativeposition of said apertures 14 in relation to said core in FIG. 4.

[0042] A more detailed illustration of said injection arrangement 35 isgiven in FIG. 5a, said illustration comprising one blank 4 out of aplurality of blanks inserted in parallel (dotted) and a jacket 8 alreadyshaped (dotted less densely), by radially oriented apertures 14 forforming support webs 14 a, in this case more clearly visible, comprisingX-shaped distributing channels 25 starting from a face end 23 of saidcore 20, from where a channel segment is formed by said sleeve body 4along a portion k1. At a lower edge of said shaping space 41, saidsleeve body is radially received by an insert 63 in a thread portion 5.Said insert is moved from a first injection molding process by arotating plate 64, positioning said sleeve body below a shaping plate 65moved axially upward, and, prior to closing said tool, said rotatingplate 64 relatively moves said sleeve body 4 (also by an axial loweringmovement of said shaping plate 65) into said shaping space 41 which isformed by an inner shaping insert 36 (finishing insert) having an innersurface 41 a simultaneously defining the shape of an outer surface ofsaid jacket 8. When inserting a core 20, an ejection sleeve 62 is alsoapplied inside a bushing at an axial end of said thread 5, for allowinga finished front portion to be ejected subsequently, after said shapingplate 65 has been lifted again.

[0043] For avoiding an early detachment of a thread 5—which in thisillustration has conical shape—of said blank when inserting said core20, said core initially does not penetrate completely into said blank 4,stopping its penetration movement into a cylindrical portion 12according to FIG. 3 at the beginning of said front portion 22 with saidcrossed channels at the latest. Prior thereto, said shaping plate 65comprising said injection insert 36 is completely placed upon saidrotation plate 64, so that the mold is closed. Then, said blank 4 is notin a position to deflect in an axial forward direction being supportedeither by an additional distribution plate 37 or by an inner wall 41 aof a cavity 41 such that said penetration movement of said core 20 canbe completed without said thread detaching from a thread support 63 ofsaid blank 4.

[0044] An injection process starts after said mold has been closedcompletely and all illustrated plates 64, 65, 37, 68 and 69 have beenplaced upon one another.

[0045] An elastomer material is injected into said refill opening ofsaid sleeve part 4 through channels 38,39 over a distribution plate 37which is in surface contact above said shaping plate 65. Above saiddistribution plate 37, a stripping plate 68 is provided, and thereabovea further plate 69 for actuating said puller core 40 is located.

[0046] After the injection process of said elastomer having beenterminated and after said elastomer having cooled down or hardened,firstly said ejection plate 68 is moved in an axially upward direction,separating the entire sprue portion 38,39,10,25, as illustrated in FIG.7, from the front part of said sleeve body and from the distributionplate 37 over said puller core 40. Said sprue remains in contact withsaid plate 68 and can also be separated therefrom by relatively movingsaid plates 68,69. Thin portions 45 a,45 b at a transition of saidsupply channel to webs 14 a of said jacket 8 form said separatingportions which are torn off by said puller core 40 when lifting saidplates 68,69. After lifting said plates 37,68,69, said shaping plate 65is also lifted, said core 20 is moved out of said readily shaped part,and said front portion is completely separated from said mold over saidejection sleeve 62. Thereupon, said rotation plate 64 is again pivotedback such that said insert 63 is positioned in a portion of said tool inwhich a preform 4 is produced using said first material.

[0047] Two separation planes FT1 and FT2 are illustrated in FIG. 5a,said first separation plane being a sprue separation plane, in which thehardened supply channels of said thermoplastic elastomer are separated,whereas said second plane FT2 is the main separation plane forseparating the mold and releasing the finished part.

[0048] An alternative core 20 according to FIG. 5a, which so far hasonly been mentioned briefly, a front portion of which core is differentfrom the embodiment according to FIGS. 4,5, shall be described in moredetail with reference to FIG. 6a. Up to a conical portion 21, said core20 is identical with that of FIG. 5. Only a top portion 22 is modifiedwith respect to an extension of the channels 25 a,25 b. FIG. 6a showssaid channel extension in an axial top plan view, and FIG. 5a is across-sectional illustration of said channels. Two crossing channels 25a,25 b are shown, said channels having a slightly conical shape andextending at an angle of 10°. Said channels extend from an end surface23 and terminate in front of a conical portion 21. To be more exact withrespect to an aperture 14, said channels terminate at a radially outerwall of a portion 22 of said core, at a distance k4 from the beginningof said aperture 14. An overlap k4 ensures that the softened materialfor said jacket 8 reaches said aperture 14. FIG. 5a shows thin portions45 a′ and 45 b′ being present in a direction towards an edge at a lowerend due to said channels 25 a,25 b being partly provided as blind holes.

[0049] In the described embodiment of the channels continuing in saidcore 20, a sprue remainder is formed, said sprue being correspondinglymodified with respect to FIG. 7, but nevertheless having two connectionarms 44 a′ and 44 b′, said arms, for simplifying a mold separation at a(relative) backward movement of said core, reflecting the conical shapeof said holes 25 a and 25 b, when (relatively) moving said core back andusing said thin portions 45 a′ and 45 b′ as separating portions.

[0050]FIG. 5b shows a further embodiment of a top portion 22 of saidcore, said embodiment for the rest being identical with that of FIG. 5aas far as the shaping tool is concerned. Also, a blank 4 is insertedinto an injection cavity 41, the path of said second material beingmarked by an arrow, said second material being conducted through anaperture 14 in said blank 4. FIG. 5b illustrates that an axiallongitudinal extension of said core, due to a conical shape 22 b of saidtop portion according to FIG. 6b, practically reaches an opening 7.Despite said core having an enlarged extension in an upward direction, acircumferential guiding of said channel portion along a length k1 andalso of an additional channel portion along a length k2 remain, thepurpose of which has so far been fulfilled by the inside of said coreand by the crossing openings described in FIG. 5a. Said blank, in a tipportion thereof, further comprises a circumferentially extending wallfor delimiting the flow of said second material, whereas a radialdeflection towards said apertures 14 is obtained due to said core havinga conical shape 22 and comprising a top portion 26. According to FIG. 5bin combination with FIG. 6b, a ring channel 27 enlarging in diameter isformed between an outer surface of said cone 22 b and an inner wall 10of said tip portion of said blank 4.

[0051] A further embodiment shall be described with reference to FIG.6c. Said embodiment fits identically on the cores of FIGS. 5,5a and 5 b,with a modified top portion 22 c, respectively, above a conical portion21 as shown in FIG. 6c.

[0052] It is visible from the top plan view of FIG. 6c that two channels27 a,27 b are adapted to extend in an axial direction, said channels notextending completely circumferentially, but only having a limitedchannel width. Said channels are open in a radially outward directionand are closed at portions 10 a, 10 b by respective opposite inner wallportions of a portion 10 of said blank 4 above a plane 11.

[0053] A tip 26 a of the embodiment 22 c of said top of the core isline-shaped, but it can have a different shape when three or fourcircumferentially distributed channels (corresponding to said channels27 a, 27 b) are present. During injection, said second material isguided in a portion k1+k2, said guiding being effected by acircumferentially delimited portion of an inner surface of said blank.An aperture 14 is only symbolically marked in FIG. 6c with regard to aheight and a position thereof, so that in a portion k4, said secondmaterial can pass over to an outer portion of said jacket 8 through saidaperture—thus into the shaping cavity 41.

[0054] Said portion k4 is only a small part of the complete length ofsaid aperture 14, particularly considerably less than one third of alength thereof.

[0055] Due to the shaping and method described, said shape-retainingsleeve body 4 can be provided in one piece, so that only two steps andtwo injection arrangements and no additional assembling steps arerequired for producing a front portion.

1. Front portion (1) of a housing of a writing instrument having anelongated refilling device, said front portion comprising a sleeve body(4) made of a shape-retaining material and a jacket (8) made of a secondmaterial, said jacket covering a surface of said sleeve body along asubstantial part of an axial length thereof, wherein (a) a front opening(7) located at a front end of a tip of said sleeve body (4) is adaptedas a starting end of an adjoining axial segment (7,10,k1) of aninjection channel (38,39,10,24,25) for said second material; (b) saidsleeve (4) comprises at least one radially oriented aperture (14) forlaterally (radially) delivering said second material to an outercircumferential portion (4 a) of said sleeve body (4).
 2. Front portionaccording to claim 1, wherein said axial segment adjoining said openingline or opening end (7) is adapted as a portion (k1) of an inner surfaceof said sleeve body (4), particularly as a portion (10) enlargingtowards the rear.
 3. Front portion (1) according to one of claims 1 and2, characterized in that said sleeve body (4) comprises two or moreapertures (14) distributed over a circumference thereof, said aperturesbeing filled in (14 a) with said second material for attaching saidjacket (8) at said sleeve body (4) to be connected by complementaryshapes.
 4. Front portion (1) according to claim 1, characterized in thatat least one of said apertures (14) has a contour (15) enlarging from anoutside towards an inside thereof.
 5. Front portion according to claim1, wherein said axial segment (7,10,k1) extends in an axial directionover a limited length (k1), said length particularly being longer thanat least one half of the diameter of said opening (7) at a front endthereof and said segment, in a circumferential direction, comprising atleast one circumferential portion (10 a,10 b;FIG. 6c) of an innersurface of said sleeve body (4) as a wall portion.
 6. Front portionaccording to claim 1, wherein said axial segment (7,10,k1) beingdelimited along an entire circumference thereof in a radially outwarddirection by a inner wall surface (10) of said sleeve body (4).
 7. Frontportion (1) of a writing instrument housing according to one of claims 1to 6, characterized in that an injection channel segment (7,10,k1) ofsaid sleeve body (4) terminates at an axial distance (k2) in front ofsaid at least one aperture (14), for being connectable with saidaperture (14) through at least one distribution channel piece (25) inthe front portion of a core (20) which is insertable into said sleevebody (4) in a direction towards said injection channel segment (7,10),said distribution channel piece having at least one of an axial and aradial—particularly an angular—orientation.
 8. Front portion (1) of awriting instrument housing according to one of claims 1 to 7,characterized in that a channel piece (24,25;25 a,25 b;27;27 a,27 b) isprovided in a front portion of a core (20), said core being insertableinto said sleeve body (4) in a direction towards said injection channelsegment (7,10,k1), said channel piece being subordinated to saidinjection channel segment (7,10,k1) of said sleeve body (4) andterminating at an axial distance (k4) behind said at least one aperture(14) for conducting said second material to said at least one aperture(14) and filling in said aperture therewith.
 9. Front portion (1) of awriting instrument housing according to one of claims 2 to 8,characterized in that said injection channel segment (7,10) enlarges indiameter by substantially 40% to 60% starting from said opening (7)along its axial length (k1), particularly starting from a diameter ofbelow 3 mm and along a length of more than said diameter.
 10. Frontportion (1) of a writing instrument housing according to one of claims 1and 8, characterized in that said material forming said jacket (8) andfilling in said at least one aperture (14), from which material saidinjection channel (7,10;k1)—particularly also said subordinated channelpiece (24,25) of said core (20) filled with said material duringproduction—is separable along an inner circumferential surface (12) overa thin portion (45 b,45 a;45 a′,45 b′) suitable for separating,particularly for shearing off, or comprises such a separating portion(45 c) invisible from outside.
 11. Front portion according to claim 1,wherein said second material for said surface-extending jacket (8) is amaterial having elastic gripping properties.
 12. Front portion accordingto claim 1, wherein said first material of said sleeve body (4) is abrittle material practically inelastic in use, such as ABS.
 13. Methodfor one of producing and shaping a front section of a writing instrumenthousing according to claim 1, according to which method (a) a sleevebody (4) made of a shape-retaining material is produced—particularly byinjection molding of a shape-retaining, inelastic plastic material—saidsleeve body comprising an opening end of an opening (7) for receiving anelongated refilling device and for radially supporting said refill, andat least one aperture (14) in a circumferential wall; (b) asurface-extending jacket (8) made of a material having elastic grippingproperties and surrounding said sleeve body (4) at an outside thereof iscircumferentially applied by radially guiding and (radially) limitingsaid material by said opening (7) along an axially adjoining section(10,k1) and conducting it (30,31) into an inside of said sleeve body(4), said material—deflected by at least one channel section in a core(20;24,25;27;25 a,25 b;27 a,27 b)—penetrating from the inside into anouter shaping space (41) through said at least one radial aperture (14)of said sleeve body; (c) said material being shaped in said shapingspace (41,41 a) to build said outer jacket (8).
 14. Method according toclaim 13, characterized in that after penetrating into said opening (7),a stream of a softened second material (31) flows inside said sleevebody, said stream particularly firstly being enlarged in cross-section(10), and subsequently being conducted radially outward (25;25 a,25 b)through said at least one aperture (14).
 15. Method according to claim13, characterized in that said sleeve body (4) is produced by injectionmolding, said aperture(s) (14) being left free by a cross-sectionalenlargement towards the inside of said sleeve body, particularly by anundercut.
 16. Method according to claim 13, characterized in that saidsleeve body is provided with several apertures (14) distributed over acircumference thereof, said apertures being filled in (14 a) forattaching said jacket at said sleeve body to fit by complementaryshapes—without a bond of material—, the material conducted out (24,25,25a,25 b,27,27 a,27 b) of the inside of said sleeve body through at leastone of said apertures reaching the remaining apertures from an outershaping space (41) thereby filling in said apertures from the outside.17. Method according to any of claims 16 to 13, characterized in thatprior to injecting said second material, the inside of said sleeve body(4), except for said opening (7) and said adjoining axial portion(10,k1), is substantially filled in by a die (20,24;25), for conductingsaid second material to said at least one aperture (14) particularly viaone of an inner shaping space or shaping cavity (24,25,25 a,25 b) in atop (22) of said die and a shape (22 b,22 c) of the front end of saidtop which is at least partly circumferentially open.
 18. Methodaccording to claim 13, characterized in that a second material is used,said material being elastically ductile (in a cooled down state) andafter injection and hardening, being separated (45 a,45 b;45 a′,45 b′)at a transition from an inside of said sleeve body to said at least oneaperture, particularly by relatively axially pulling out or extracting(40) a sprue channel segment (45) and a supply segment (44 a,44 b)thereof, said channel segment leading to said at least one aperture andhaving at least a radial orientation.
 19. Method according to claim 18,said removed channel segment (45) having a cone section (45 k) which isoriented opposite to a mold separating direction and corresponds to anenlargement (10) of said sleeve body.
 20. Method according to claim 13,wherein a hardened channel segment (45) made of a second material isremoved (40) from an axial section (10,k1) by applying a force, andseparated from said radial aperture.
 21. Method according to claim 13,wherein said sleeve body (4) is introduced into said shaping space (41),whereupon a core (20) moves (46) into said sleeve body (4).
 22. Methodfor an injection process according to claim 21, wherein said core (20)for predetermining an injection channel structure in a front end portionof said sleeve body (4) is initially not completely inserted into saidsleeve body (4) supported at a rear end thereof, when closing saidshaping space (41), said sleeve body (4) is supported at a front end bya wall of said shaping space (41), whereupon said core being completelyinserted into said sleeve body without pushing said body out of asupport (63) supporting said sleeve body (4) at a rear end thereof. 23.Method according to claim 13, said front portion being a portion of anelongated housing shaft.
 24. Tool for one of producing and shaping afront portion of a writing instrument housing according to claim 1 orfor carrying out a method according to claim 13, said tool comprising aninjection cavity (41,41 a) into which a sleeve-shaped blank (4) having afront opening (7) and a radial dimension that is smaller than saidinjection cavity (41) is insertable; an elongated core (20,22) forsubstantially filling up said blank at an inside thereof, said core(20,22) being adapted or having only a limited length such that aremaining axial length (k1) remains in front of said core or laterallyat a front end (k2,22 c) thereof, said remaining axial length beingdelimited by said blank up to said front opening (7), for guiding asoftened second material which is supplied through said opening (7) andfor delimiting said material in its radial extension.
 25. Tool for oneof producing and shaping a front section of a writing instrument housingaccording to claim 1 or for carrying out a method according to claim 13,wherein the tool has an injection cavity (41,41 a) adapted to receive asleeve shaped blank (4) having a front opening (7) and a radialdimension that is smaller than said injection cavity (41), said toolfurther comprising an elongated core (20,22) for filling up an inside ofsaid blank to support it, said core (20) having a front end (22,22 b,22c) and being adapted at said front end such that along a remaining axiallength (k1,k2), a diameter is smaller by an amount to guide a softenedmaterial (30)—which is supplied through said opening (7)—in its radialextension by at least one portion (10 a,10 b) of an inner circumferenceof said blank.
 26. Tool according to claim 25, said core, at a front endthereof, having a diameter of zero along a remaining length (k1),therefore not extending into said section.
 27. Tool according to one ofclaims 25 and 24, said elongated core (20) having a top portion (22;22a,22 b,22 c) comprising an inner channel piece (24,25;25 a,25 b), acircumferentially oriented, annular supply channel (27) located at anoutside of said top portion or at least one, preferably two radiallyopen channels (27 a,27 b).
 28. Tool according to claim 27, said topportion (22) being rotationally symmetrical and having an acute end (22b,26) or said radially open channels (27 a,27 b) having a respectivechannel bottom which substantially continuously increases in heightstarting out from a tip (26 a) in a radially outward direction.
 29. Toolaccording to claim 27, said core, behind a remaining length (k1) infront of said core or in case of a core diameter of zero, comprises twocrossing conical channel bores (25 a,25 b) as an inner channel piece,said bores being adapted to extend at an angle with respect to an axisof said core and protrude laterally out of said core at an axial heightof said at least one aperture (14), for forming separable sprue segments(45 a′,45 b′) for said second material.
 30. Shaping of a front section(1) of a housing of a writing instrument having a “refill” protrudingthrough said front section, said front section (1) comprising a refillopening (7,10) open at a front end, for receiving and radiallysupporting said refill which is particularly axially movable, a grippingjacket (8) being attached around a blank, particularly a sleeve body(4), made of a shape-retaining material, said attachment between thematerial of said gripping jacket (8) and the material of said blank (4)not being a bond of materials, such that an axial portion (k1,k2) ofsaid refill opening (7,10) serves as a guiding channel wall piece forthe material of said gripping jacket (8), said material—which isinjected under pressure through said refill opening (7)—shaping saidgripping jacket (8) on a surface of said blank (4).
 31. Shapingaccording to claim 30, wherein a diameter of said refill opening (7) issmaller than 3 mm.
 32. Shaping according to claim 31, wherein saidconducting channel piece (7,10,k1), in which said material is conductedby said blank (4) is longer than a diameter of said front end (7) ofsaid refill opening (7).